Telephone-exchange system



Dec. 29 1925- 4 P. C. SMITH TELEPHONE EXCHANGE SYSTEM Filed Oct. 12. 1925 5 Sheets-Sheet 1 5 Sheets-Shegt 2 fizz/afar: P? y 6027/77;

P. C. SMITH Filed 001:. 12. 1923 TELEPHONE EXCHANGE SYSTEM Dec. 29 .1925- TELEPHONE EXCHANGE SYSTEM ed Oct. 1 t e-Sheet 5 5 Sheets- Sheet 4 fie cam/w .mmh Mm QM P. c. SMITH TELEPHONE EXCHANGE SYSTEM Flled Oct 12 1923 Dec. 29 1925- P. C. SMITH TELEPHONE EXCHANGE SYSTEM Filed Oct. 12, 1925 5 Sheets-Sheet 5 Patented Dec. 29, 1925.

UNITED STATES PATENT OFFICE.

PERCY C. SMITH, OF EAST ORANGE, NEW JERSEY, ASSIGNOB TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Application filed October 12, 1923. Serial No. 668,072.

' and exact description.

This invention relates to telephone ex change systems and more particularly to systems in which automatic switches are employed for setting up talking connections.

In large exchange areas in which power driven switches of the revertive impulse control type are employed, controlling mechanisms of the well known register type are employed at the central oflice to control the several selective movements of the switches. The function of the register sender is to receive the record of the desired call and to thereupon control the selective switches in correspondence with the registered designation to extend a connection to the wanted line or office. In semi-automatic systems where calls are first received by or are communicated to an operator, the record is set up on the registers by means of a keyboard manipulated by the operator. In offices that are provided, however, with switches alone for performing the necessary extension of calling lines, the record must be produced on the registers of the central ofiice sender by means of impulses transmitted to the sender directly from the calling subscribers substation.

The complete designation or number relating to a particular call may be considered as consisting of two parts. The first includes one or more digits and serves to identify the particular oiiice in the exchange that contains the wanted line. The second part is the number of the wanted line in the selected office. The first part or the ofiice code, as it is called, is recorded on registers of the sender in the office of the calling line and determines the selective movement of switches in that office to select a trunk leading to the outlyin office identitied by the recorded code. Thereafter, the

sender controls Switches or other devices in the distant ofiice in accordance with the numerical or second part of the designation to cause a further extension of the connection. In order that the requisite number of ofiice codes may be registered to determine the routing of connections to outlying 0ffices and to care for the various classes of calls involved and to secure a flexible arrangement, whereby these routings may be altered from time to time without the necessity of complex wiring changes and in order that the several otlice code and numerical digits may be recorded, a unitary switch of the coordinate type is provided to record all office and numerical designations.

An object of the invention is, therefore, to provide in a system of the above described character, a unitary registering mechanism for recording all digits of the office and numerical designations of all desired connections.

A further object of the invention is to provide a unitary registering mechanism which is capable of making the necessary oflice code and class of call translations without the employment of other translating means.

A feature of the invention relates to the provision of a switch of the coordinate type, the vertical bars of which are set successively and repeatedly in response to the suc cessive digits dialled and the horizontal bars of which are set successively in response to successive series of impulses whereby cards are lifted to establish the desired registrations.

Other and further features contemplated by the present invention will appear from a consideration of the following description.

Referring to the drawings, Figs. 1 to 5, when taken with Fig. 2 at the right of Fig. 1, Fig. 3 beneath Fig. 2, Fig. 4: at the right of Fig. 3 and Fig. 5 beneath Fig. 4, illustrate such portions of the circuits and apparatus of a telephone exchange oflice as are considered necessary to an understanding of the present invention.

Fig. 1 shows a calling subscribmfs lino terminating in an individual line switch adapted to extend the line to an idle trunk circuit,

Fig. 2 illustrates a trunk circuit accessible to the individual line switch and tern'iinatingin a district selector switch. This figure also shows a step-by-step sender selector switch for associating the circuits of the district selector with one of a plurality of register sender mechanisms.

Fig, S- illustrates a sender and controlling mechanism arranged to receive series of impulses transmitted over a calling subscribers line to record the ofiice and numerical designations of a wanted subsci'ibers line, and to control the automatic switches for the purposeof extending a connection in ac cordance with the registered designations. This figure also illustrates aclass switch, the function of which is to govern the sending mechanism in accordance with the class of the call recorded.

Figs. 4 and 5 taken. together show a unitary registering mechanism for recording the otfice code and numerical digits dialled by the calling subscriber. Fig. 5 also shows a plurality of recording relays for temporarily recording the impulses dialled by the subscriber'in each digit series and circuit connections therefrom for controlling the setting of the registering mechanism.

The individualline switch in Fig. 1 and ,the district switch in Fig. 2 respectively are in general of the same type as disclosed in Patent No. 1,395,977 issued November 1, 1921 to F. A. Stearn and F. J. Scudder.

The sequence switches'QlO, 310 and 350 are of the same type asthat illustrated in detail in the patent to Reynolds and Baldwin No. 1,127,808,patented Februaiy 9, 1915. Thesequence switch, 210 controls the contacts showiijiii Fig.2,sender sequence switch 310 controls the contacts shown to the right and abovethebrokenline in Fig. 3 and the classsequence switch 850 controls the contacts shown to the left and beneath the broken line in Fig. 3.

"Tlie' chain of transfer relays comprising eightpairs'shown in the lowei portion of Fig. serves as a progression switch for controlling the successive registrations of the several digits of thedesired line designation upon the registering'inechanism of Figs. sand 5. A pair of'these relays operatesin response to each series of impulses dialed by the subscriber.

The registering mechanism disclosed in Figs. 4: and is of the coordinate switch type and more particularly of the type disclosed in the patent to C. L. Goodrum and C. J. Hendrickson, No. 1,528,763, issued March 10,1925. This switch comprises ten' groups of vertically disposed bars, each group comprising ten bars, and seventeen horizontal bars. The numberof horizontal bars may, however, be increased to include additional bars when it is desired to record additional stations digits for P. A. X operation. Each of the horizontal bars is operated by a magnet individual thereto and shown at the left end of each bar respectively. Each of the vertical bars is divided into two sections, which may be coupled-together through the operation of some one of the upper ten horizontal coupling bars in the manner disclosed in the aforesaid patentto Goodwin and Hendrickson. The upper sections of the ten vertical bars of each" group are linked together for rotation by an operating magnet common to the ten bars of each group. Thus, ten vertical operating magnets are provided. For conciseness in illustration, only the first six vertical bars of the 'No. 1 group, the last four bars of the N o. 8 group and the last four bars of the No. 9 group have been illustrated.

' Associated with each of the lower seven horizontal bars which will hereinafter be termed recording bars a plurality of grid wires is provided, these wires extending entirely across all of the hundred vertical bars and cooperating with contacts disposed at thejunctions of the vertical bars with the horizontal recording bars. At these junction points, the contacts extend through micarta cards which are arranged to lift them into contact with the corresponding grid wires upon the conjoint operation of the particular vertical and horizontal bars adjacent such, junction points. For example, cards andh sociated contacts are provided at the junctions of each of the hundred vertical bars with the upper two horizontal recording bars shown in the lower portion of Fi 1-, there being therefore, 200 of these cards. These cards are employed to record any one otQOO office designations. A card is similarly located atthe junction of each of the five recording bars shown in Fig. 5 with the first bar of the first group of ten vertical bars, with the second bar ofthe second group often vertical bars, and with the third bar of the third group of ten vertical bars etc.

No cards and contacts are located at the jdnCtlQllSOf: the remaining vertical bars and 'therecfording bars of Fig. 5. The ten cards associated with the upper horizontal bar of Fig. 5 are employed to record the thousands digits of wanted line designationsand the tleii'cards associated with each of the successively lower disposed bars of Fig. 5 are employed for recording hundreds, tens, units and stations digits respectively. The contacts of all of the cards are cross-connected to the sender counting relays, to the contacts of the class sequence switch, and to the relay call indicator 'impulser of the sender as required, in the well known manner.

For example, if-it is desired to record the office code TUX; corresponding to the digits 889, the No. 8 horizontal operating magnet is first operated inresponse to the first digit 2 followedby the operation of the Not vertical operating magnet in response to the second digit 8. The operation of the No. 8 horizontal magnet results in the camming of the couplers of the No. 8 vertical bar in each of the ten groups of vertical bars so that the two sections of each of these vertical bars are coupled together. lVhen thereafter, the No. 8 vertical magnet is operated, the vertical bars of the eighth group are operated, but since only the No. 8 bar of this group has its two sections coupled at this time, only the lower section of the N0. 8 bar is operated. In response to the third digit 9, the uppermost horizontal recording bar is rotated, thus resulting in the operation of the card at the junction of this bar with the No. 8 vertical bar in the eighth group. In this connection, it may be noted that the uppermost recording bar is operated whenever the third code digit is odd and the next lower recording bar is operated whenever the third code digit is even.

The chain of relays shown in the lower portion of Fig. 5 serves to record the number of digits dialled by the calling subscriber in each digit series, and at their contacts transfer such record to the registering mechanism. These relays are arranged in pairs, a pair operating in response to each digit impulse dialled by the subscriber.

lVhile only a single selector switch has been disclosed in Fig. 2 for extending connections from a calling line, it is to be understood that other selector switches would be employed, these switches comprising an ollice selector. an incoming selector and a final selector. These additional switches have, for the sake of conciseness, leen omitted from this disclosure. Reference may be had to the hereinbefore mentioned patent to Stearu and Scudder for a full disclosure of these switches.

Having given a general explanation of the system and of the apparatus employed therein, it is believed that the invention may be bestunderstood by a detailed description of the operations concerned in the c: tension of a connection. For this purpose, it will be assumed that the subscriber at station A desires a connection with a subscriber whose line te'ininates in an office of the full mechanical type identified by the oiiice code TUX having equivalent numerical values 889 and that the number of the subscribers line in that oitice is 9189.

To initiate a call, the subscriber removes his receiver from the switchhook whereby a circuit is established from battery, through the right winding of line relay 103. back contact and inner lower armature of relay 10 1 over the loop of the callingsubstation A to ground at the upper armature and back contact of relay 104. Relay 103 becomes energlazed and completes a circuit from batterv through the winding of stepping magnet 105,

armature and contact of said magnet, lowerinost armature and contact of relay 101, right armature and front contact of relay 10 5, to ground through the brush 111 and terminal 114. Magnet 105 energizes, interrupts its own circuit, decnergizes and steps the brushes 106, 107, 108, 109, 110 and 111 forward one step. Brusn 109 thereupon engages the segment. 113 and battery potential is supplied to the test terminal 102 of the calling line in the multiple banks 01 panel selector switches having access to this line. In this manner, the calling line is rendered busy. The above t'aced circuit is again completed for magnet 10;) by way of brush 111 and terminal 110 and the switch continues to the next set of terminals which represent the l'irst of a plurality of trunk circuits leading to selector switches. bio long as the individual switch encounters the terminals of busy trunks, brush 111 finds a ground potential on the test tern'iinals 120 01 such trunks and the switch continues to rotate. When the tirst idle trunk 115, 116 is reached, no ground potential is present on terminal 120 and consequently, the stepping magnet 105 ceases to advance the switch.

Since the trunk 115, 110 is idle. the sequence switch 210 of the district switch asso ciated with such trunk is standing in position 1. A circuit is then traceable from battery, through cam contact .203. back contact and left armature of relay 200. conductor 1.18, tcri'ninal 120, brush 111, contact and loft armature and left winding of relay 1023, through both windings o1 relay 10-1- in series, to ground. clay 10:' becomes energized in this circuit and locks in a circuit extending from battery, through the winding oi' relay 200, left make-betore-break contact o1 relay 20-3, lower contact of ram 215. condiwtor 117. terminal 121, brush 110, middle lower arma ture and contact of relay 10-1, upper winding of said relay to ground. Relay 10-1 therefore, remains energized. while relay 200 attracts its arinatures. Relay .200 at its left armature and back contact opens the circuit through the winding of relay 10?) which caused the original energization of relay 101. Relay 103 consequently becomes dcenergized.

Relay 200011 attracting its armat-ures completes a circuit from battery through the right winding of relay 212, lower contact of cam 21 1, upper contacts of cam 205- to ground at. the right armature and contact of relay 200. Relay 5212 becomes energized and closes a circuit from battery, through the winding i"? sequence switch magnet 210, left contact of cam 215, right armature and trout contact of relay 212 to ground at the lower contact of cam 213. Sequence switch 210 advances from position 1 to position whereupon a. holding circuit is closed from ground over the upper left contact-ct cam i300 and conductor 118 tomultiples of terminal 120 to hold the trunk busy. If the test brush 241 of the sender selector switch chances to be standing on the terminals of a busy sender at this time, relay 207 of some other switch is energized as will be later explained, and a circuit is provided for maintaining the operation of relay 212. This circuit may be traced from battery, through the left winding, left armature and contact of relay 212, upper left contact of cam 251, lower contact of cam 220, conductor 252, brush 241, thence over the multiples of the test terminal to the brush 241 of the sender selector-render ing said sender busy, to ground at the inner left armature of the operated relay corresponding to relay 207. Relay 212 remains energized in position 2 of sequence switch 210 and in so doing provides a circuit for the stepping magnet 211 for advancing the brushes of the sender selector switch to search for the terminals of an idle sender. The circuit for magnet 211 may be traced from battery, through the contact and armature and Winding of said magnet, conductor 253, left contact of cam 218, right armature and front contact of relay 212 to ground at the lower contact of cam 213. At the same time a circuit is maintained from battery, through the contact, armature and winding of ma net 211, through the winding of relay 20( to ground at the lower contact of cam 209. Due, however, to the shunt provided by the above traced circuit, suificient current does not flow through the winding of relay 207 to energize the latter. Stepping magnet 211 interrupts its own circuit and advances the brushes of the sender selectorv in a step-by-step movement in search for an idle register sender. When the first idle sender is reached, relay 212 becomes deenergized since no ground potential is found on the multiple terminal engaged by the brush 241. Relay 212 opens .the direct circuit to ground for magnet 211, the magnet 211 now being included in series with relay 207. Magnet 211 does not continue to operate in View of the high resistance of relay 207. Relay 207 at its inner left armature applies a ground potential to the test terminal to render the selected sender busy to other sender selector switches. Relay 212 on retracting its armatures completes a circuit as follows for driving sequence switch 210 out of position 2 into position 3: battery through the winding of said sequence switch magnet, right contact of cam 215, back contact and right armature of relay 212 to ground at the lower contact of cam .213. Relay 207 also closes a circuit from ground over its inner left armature, brush 241, contacts 303 of the class switch 350, winding of relay 302 to battery and ground. Relay 302 looks over its inner armature and at its outer armature closes a circuit by way of the upper left contact of cam 308 for driving class sequence switch 350 into position 3.

An idle sender having been selected, and with the sequence switch 210 in position 3, an impulse circuit is established from the calling subscribers line, through to the impulse relay 300 of said sender. This circuitmay be traced from battery through the windingof impulse relay 300, brush 240, outer left armature and contact of relay 207, lower contact of cam 201, conductor 116, terminal 122, brush 108, front contact and inner lower armature of relay 104 through the loop of substation A, upper armature and front contact of relay 104, brush 106, terminal 123, conductor 115, left contact of cam 200, brush 239, right winding of coil 301 to ground. Relay 300 becomes energized and completes a circuit over its armature and front contact fort-he slow-to-release relay 304. Relay 304 at its left armature and contact completes a circuit from ground through the left winding of coil 301 and the right winding of tone coil .375. Current flowing in this circuit induces current in the right winding of coil 301 which is transmitted over the impulse circuit above traced to produce a characteristic sound in the calling subscribers receiver. This sound indicates that a sender has been associated with the calling line and that the subscriber may proceed to transmit impulses. Relay 300 upon energizing, in addition to closing a circuit for relay 304 connects ground to con duc-tor 526 for a purpose to be later explained.

The subscriber, thereupon, operates the sending dial 101 to transmit the first digit 8 of the code identifying the ofiice in which the called line appears. The first interruption of the impulse circuit causes the deenergization of relay 300, which at its armature and back contact, establishes a circuit extending through the inner right armature and front contact of relay 304, thence in parallel through the winding ofrelay 305 to battery and over conductor 306, the intermediate armature and back contact of relay 505 to battery through the winding of recording relay 506. Relay 506 thereupon energizes closing a locking circuit for itself extending from battery through its winding, the winding of relay 505, the intermediate armature and contact of relay 506, conductor 525 to ground at the armature and contact of relay 306, the relay 306 having energized immediately following .theenergization of relay305. Relay 505 does not energize in the locking circuit of relay 506 since it is at the time shunted by direct ground at the armature and back contact of relay 300. Upon the termination of the first impulse of the first digit series, relay 300 again energizes opening the ,shuntarolmd the Winding of recording relay 505, whereupon this relay energizes in the locking circuit of relay 506. In response to the remaining impulses of the first code series, relays 507 and 508, 509 and 510, 511 and 512, etc. energize in pairs until relay 519 energizes upon the termination of the 8th impulse of the first code series.

During the interval between the dialing of the first and second series of impulses relay 300 remains energized for a sufficient time to permit the deenergization of slow releasing relay 305 which, at its right armature and back contact, establishes a circuit for relay 307 which may be traced from battery, right armature and back contact of relay 305, relay 307, conductor 303, uppermost armature and back contact of relay 326, uppermost armature and back contact of relay 324, upper most armature and front contact of relay 505, conductor 526 to ground at the armature and front contact of relay 300. Relay 307, upon energizing, establishes a circuit for the transfer relay 312 which may be traced from battery through the winding of relay 312, the lower armature and back contact of relay 309 to ground at the armature and front contact of relay 307. Relay 312, thereupon, locks in series with relay 309 over the upper armature and contact of relay -312, conductor 311 to ground at the outer right armature and contact of relay 304. Relay 309 does not, however, energize in the locking circuit of relay 312, since it is shunted by direct ground at the armature and front contact of relay 307. lVith relay 309 deenergized and relay 312 energized a circuit is extended from ground at the upper armature and contact of relay 309, over the lower armature and contact of relay 312, conductor 327, the upper armature and front contact of relay 506, the upper armature and front contact of relays 508, etc., upper armature and front contact of relay 520, upper armature and back contact of relay 522, conductor 528 to battery through the winding of magnet 404. Magnet 404, upon energizing, locks itself to ground through its armature and contact, conductor 408, thence to ground at the upper armature and back contact of relay 315. Relay 404 also rotates the coupling bar 410 to effect a coupling between the sections of the No. 8 vertical bars in each of the ten groups of vertical bars.

A moment later slow releasing relay 306 whose circuit was opened following the deenergization of relay 305 deenergizes, removing locking ground from conductor 525, thereby releasing all recording relays 506 to 5120 inclusive, which have been previously energized. The initial energizing circuit of magnet 404 is thereupon opened at the contacts-of the recording relays. In response to the first impuls of the second code digit series relay 300 dcenergizes opening the circuit of relay 307 which innnediately deenergizes opening the shunt around the winding of transfer relay 309, permitting relay 309 to energize in the holding circuit of relay 312. Relay 309, upon energizing, also opens at its upper armature contact the cir' cuit over conductor 327 over which the magnet 404 was initially operated.

lVith relay 300 deenergized in response to the first impulse of the second digit series, relays 305 and 506 again operate, rclay 500 locking in series with relay 505 to ground on conductor as before described. In response to the ren'iaining impulses of the second digit series, relays 507 and 508, etc. operate in pairs until the eighth pair 519 and 520 operate and lock to ground on conductor 525. \Vhen relay 300 remains energized at the termination of the last impulse of the second digit series, relay 305 deenergizes closing the circuit of relay 307 whereupon a circuit is established for the transfer relay 314 extending from battery through the winding of relay 314, the lower armature and back contact of relay 313, the lower armature and front contact of relay 309, to ground at the armature and front contact of relay 307. Relay 314 thereupon locks in series with relay 313 to ground on conductor 311, but relay 313 being shunted at the front contact of relay 307 does not operate at this time.

lVith relay 314 energized a circuit is closed from ground at the upper armature and back contact of relay 313, the lower armature and front contact of relay 314, conductor 328, the lower armatures and front contacts of relay 505, 507-519, the lower armature and back contact of relay 521, conductor 520 to battery through the left winding of vertical magnet 401. Magnet 401, upon energizing, looks over its right winding and right armature contact to ground on conductor 408 and rotates the upper sections of all ten vertical bars of the eighth group associated with this magnet. Since only the sections 411 and 412 of the No. 8 bar of this group have been coupled by the prior operation of the horizontal coupling bar 410 only the lower section of the eighth vertical bar in the eighth group is rotated. Upon the rotation of this bar 412 the pins projecting therefrom, such as shown at 430, are positioned beneath the corresponding card such as shown at 431. A moment later relay 300 whose circuit was opened upon the deenergization of relay 305 retracts its armature opening the locking circuit of all operated recording relays 505 to 520 inclusive. Relays 505 etc., upon decnergizing open the initial energizing circuit of magnet 401 but the magnet 401 is maintained operated over the locking circuit previously traced. In response to the first digit of the third code digit series, relay 300 deenergizes, opening the circuit of relay 307 which immediately deenergizes opening the shunt around the winding of transfer relay 313, permitting this relay to energize in the holding circuit of relay 314.

With relay 300 deenergized relays 305 and 506 are again energized, relay 506 locking as before in series with relay 505. Following the termination of this first impulse of the third digit series relay 300 again energizes removing the shunt from relay 505 which energizes in the locking circuit of relay 506. In response to the remaining impulses of the third digit series the digit having been assumed to be 9, relays 507 and 508, etc. operate in pairs until the ninth pair 521 and 522 operate and lock.

IVhen relay 300 remains energized at the termination of the last impulse of the third series, relay 305 deenergizes as before, closing the circuit for relay 307, which in turn, closes a circuit for transfer relay 316. This latter circuit may be traced from battery through thewinding of relay 316, the lower armature and back contact of relay 315, the lower armatures and front contacts of relays 313 and 309 to ground at the armature and front contact of relay 307. Relay 316, upon energizing, locks in series with relay 315, to ground on conductor 311, relay 315, however, not operating at this time since it is shunted by direct ground at the armature and front contact of relay 307. With relay 316 energized a circuit is closed for the odd horizontal code recording magnet 406 which may be traced from ground at the intermediate armature and back contact of relay 315', the lower armature and front contact of relay 316, conductor 329, lower armature and front contact of relay 522, conductor 532, the right winding of magnet 406 to battery. Magnet 406, upon energizing, looks over its left winding and left armature contact, conductor 409, brush 241 to ground at the intermediate armature and contact of relay 207. Magnet 406 also rotates: the bar 413 lifting the arm 414 into engagement with pin 430 thereby lifting card 431. A moment later relay 306 whose circuit was opened by the deenergizationof relay 305 retracts its armature opening the locking circuits of all operated recording relays 505 to 522, inclusive, and in turn the initial operating circuit of magnet 406.

In response to the first digit of the fourth or thousands digit series, relay 300 deenergizes, opening the circuit of relay 307 which momentarily deenergizes opening the shunt around relay 315, permitting relay 315 to energize in holding circuit of relay 316. Relay 315, upon operating, removes locking ground from conductor 408 whereupon the I operated magnets 404 and 401 are released,

restoring the horizontal coupling bar 410 and the operated vertical bar 412 to normal position. Since, however, magnet 406 is still locked energized, the arm 414 maintains the card 431 in its lifted position re- ;gjardless of the restoration of vertical bar It is to be noted in this connection that had the third code digit been even in value, for example, two, then when relay 316 energized a circuit would have been completed for the even horizontal code recording magnet 407 from ground at the intermediate armature and back contact of relay 315, the lower armature and front contact of relay 316, conductor 329, the lower armature and front contact of relay 508, conductor 530 to battery, through the right winding of magnet 407. Thus, the first two code digits determine which of one hundred code cards in either one of the two horizontal rows of K cards is to be selected, and the third code digit determines which row of cards is to be selected. In this manner any one of two hundred codes may be selected, the third code digit selecting the upper row 'of-cards if the digit is odd, ,andselecting the lower row of cards if the digit is even. In this connection it may be noted that since the code digits dialed for any ofice designation correspond to the first three letters of the cities name, it would be possible, for example,

to dial TUC or 832 for TUCker, TUF or 883 for TUF ts, TUI or 884 for TUIleries, TUL or 885 for TULly, TUN or 886 for TUNnel, TUS or 887 for TUScon, TUT or 883 for TUTtle or as described TUX or 889- for 'IUXedo. The first two letters would, inthe examples chosen, remain the same for each code and the last letter would vary in numerical value from 2 to 9. It would, however, be possible to employ only two of the suggested 061% names in the telephone directory, since it is possible to register only a choice of two of these names, but any two could be chosen provided the last letter of one name has an odd numerical equivalent, and the other has an even numerical equivalent. Obviously by providing ten horizontal rows of one hundred cards each and ten corresponding code recording magnets similar to magnets 406 and 407 connected to contacts of the recording relays in the same manner as the magnets 403, 404, etc. or magnet 400, 401, etc. any one of one thousand codes could be selected.

With relay 300 deenergized, relays 305 and 506 again energize, relay 506 locking in series with relay 505 to ground on conductor 525 as before described. In response to the remaining impulses of the fourth digit series, the digit having been assumed to be 9, relays 507 and 508, etc. operate and lock in pairs until the ninth pair 521 and 522 operate and lock. When relay 300 remains energized at the termination of the last impulse of the fourth or thousands series, relay 305 deenergizes closing the circuit of relay 307, which in turn, closes a circuit for relay 318, this latter circuit may be traced from battery, winding of relay 318, the innermost upper armature and back contact of relay 317, the lower armatures and front contacts of relay 315, 313 and 309 to ground at the armature'and front contact of relay 307. Relay 318, thereupon, energizes and locks in series with relay 317, to ground on conductor 311 but relay 317 being shunted by direct ground at the armature and front contact of relay 307 does not energize at this time. ,lVith relay 318 energized a circuit is closed for the No. 9 horizontal coupling magnet 405 which may be traced from ground at the upper intermediate armature and back contact of relay 317, the lower armature and front contact of relay 318, conductor 327, the upper armatures and front contacts of relays 506, 508522, the upper armature and back contact of relay 524, conductor 531, winding of magnet 405 to battery. Magnet 405 energizes, looks over its armature and front contact, conductor 408, the upper armature and front contact of re lay 31.5 to ground at the upper armature and back contact of relay 317 and rotates coupling bar 416. At the intermediate armature and front contact of relay 318, a circuit is also established over conductor 321 to battery through the winding of slow operating relay 330. This relay after an interval at tracts its armature connecting ground to conductor 328 thereby establishing a circuit over the lower armatures and front contacts of relays 505, 507521, the lower armature and back contact of relay 523, conductor 533 to battery through the left winding of magnet 402. Magnet 402 thereupon energizes, locking itself over its right winding and right armature contact to ground on conductor 408 and rotates the upper sec tions of all vertical bars in the No. 9 group. Since both the No. 9 coupling bar 416 and the upper sections of the No. 9 group of vertical bars are now operated, the upper and lower sections 417 and 418 of the No. 9 vertical bar in theninth group are coupled and operated together, positioning the pins such as'534beneath their respective cards such as 535. It is to be noted in this connection that for all digits of numerical designations correspondingly numbered coupling magnets and vertical bar magnets are successively operated.

A moment later the relay 306 whose circuit was opened upon the deenergization of relay 305 retracts its armature opening the locking circuit of all operated recording relays 505 to 522, inclusive, whereupon these relays release, opening the initial operating circuits of magnets 402 and 405. In response to the first impulse of the fifth or hundreds digit series relay 300 deenergizcs, opening the circuit of relay 307 which momentarily deenergizes, opening the shunt around relay 317. Relay 31.7 thereupon energizes in the locking circuit of relay 316 and at its lower armature and contact closes a circuit extending from ground at the armature and back contact of relay 307, arn'iature and front contact of relay 317, lower armature and back contact of relay 319, conductor 332, thence to battery through the right winding of thousands recording magnet 500. Magnet 500, thereupon, energizes locking itself to ground on conductor 400, over its left winding and left armature contact and rotating the thousands recording bar 530. lVith the bar 536 and the bar 418 conjointly operated, the card is lifted. A moment later relay 317 opens its upper arm aturc con- .act, thereby removing locking ground from conductor 408 and releasing magnets 402 and 405, whereupon these magnets release, restoring the operated bars 416 and 418 to their normal positions. The operated card is, however, maintained in its operated position since the magnet 500 is locked at this time. In this connection it may be noted that the circuits for the recording bar magnets must be closed just prior to the release of the coupling bar and vertical bar magnets and for this purpose the lowermost contacts of relays 317, 319, 321, 323 and are arranged to close before the upper contacts of these relays open.

\Vith relay 300 deenergizcd upon the first impulse of the fifth digit series, relays 305 and 500 again energize, relay 500 locking in series with relay 505. lVhen relay 300 again energizes upon the termination of the single impulse of this series. the hundreds digit having been assmned to be 1, relay 305 dc energizes closing the circuit of relay 307 which, in turn, closes a circuit for transfer relay 320. This circuit may he traced from battery, winding of relay 320, innermost upper armature and back contact of relay 310, innermost upper armatures and from. contacts of relays 317, 315, 313 and 300 to ground at the armature and front cont act of relay 307. Relay 320, upon (-mergizing. locks in series with relay 310 to ground on conductor 311, but since relay 310 is shunter at this tine at the armature and front con tact of relay 307, it does not energize. ll'iih relay 320 energized a circuit is closed for the coupling bar magnet 4-03 which may be traced from ground at the intermediate upper armature and back contact of relay 310, the lower arn'iature and front contact of relay 320, conductor 327. the upper armal me and front contact of relay 500. the upper armature and back contact of relay 508, conductor 527, to battery through the magnet 403. Magnet 403 locks over conductor 408. the upper arniatures and front contacts of relays 315 and 317 to ground at the upper armature and back contact of relay 319. At its intermediate armature and front contact, relay 320 closes a circuit as previously traced for relay 330 which after an interval connects ground to conductor 328. A circuit isnow established from ground on conductor 328 over the lower armature and front contact of relay 505, the lower armature and back contact of relay 507, conductor 537 to battery through the left winding of magnet 400. The magnet 400 energizes and locks itself to conductor 408. The successive operation of magnets 403 and 400 causes the operation of the No. 1 bar 419 in the first group of vertical bars. A moment later relay 306 whose circuit was opened upon the deenergization of relay 305 retracts its armature opening the lockingcircuit of recording relays 505 and 506, which in turn, open the initial operating circuits of magnets 400 and 403.

In response to the first impulse of the SlXbll or tens digit series, relay 300 deenergizes, opening the circuit of relay 307 which deenergizes, opening the shunt around relay 319, permitting this relay to energize in the locking circuit of relay 320. Relay 319 at its lower armature and front contact closes a circuit extendingfrom ground at the armature and back contact of relay 307, the lower armatures and front contacts of relays 317 and 319, the lower armature and back contact of relay 321, conductor 323 to battery, through the right winding of hundre ds recording magnet 501. Magnet 501, upon energizing, looks over its left winding and left armature contact to ground on conductor 409 and rotates the hundreds recording bar 539. This bar in cooperation with the operatedyertical bar 419 lifts the card 538. A moment later relay 319 opens its upper armature contact removing locking ground from conductor 408 thereby releasing magnets 400 and 403. These magnets thereupon permit the restoration of the operated vertical bar 419 and the operated coupling bar. The bar 539, however, is maintained operated since magnet 501 is still locked.

With relay 300 deenergized relays 305 and 506 again energize, relay 506 locking in series with relay 505 to ground on conductor 525. IV hen relay 300 again deenergizes relay 505 energizes. In this manner in response to each impulse of the tens digit series, the tens digit having been assumed to be 8, the recording relays operate in pairs until the relays 519 and 520 are operated. Vhen relay 300 remains energized at the ter- .mination of the last impulse of the series,

relay 305 deenergizes as before described closing the circuit of relay 307. lVith relay 307 energized a circuit is now established for transfer relay 322 extending from battery through relay 322, the innermost upper armature and back contact of relay 321, the innermost upper armatures' and front contacts of relays 319, 317309 to ground at the front contact of relay 307. Relay 322,

upon energizing, locks in series with relay 321, to ground on conductor 311 but relay 321 being shunted at the armature and front contact of relay 307 does not energize so long asrelay 307 remains energized.

With relay 322 energized a circuit is closed for the No. 8 horizontal coupling magnet 404 which may be traced from ground at the upper intermediate armature and back contact of relay 321, the lower armature and front contact of relay 322, conductor 327, the upper armatures and front contacts of relays 506, 508-520, the upper armature and back contact of relay 522, conductor 528, to battery through the winding of magnet 404. Magnet 40 4, upon energizing, locks to ground over conductor 408, the upper armatures and front contacts of relays 315, 317 and 319 and the upper armature and back contact of relay 321 to ground. At its intermediate armature andv front contact, relay 322 establishes the previously traced circuit for relay 330, which at its armature and contact, grounds conductor 328. A circuit is now established over conductor 328, the lower armatures and front contacts of relays 505-519, the lower armature and back contact of relay 521,. conductor 529 to battery through the left winding of magnet 401. Magnet 401, upon energizing, locks to ground onconductor 408. Through the conjoint operation of magnets 404 and 401 the vertical bar 412 is operated in the manner previously described. A moment thereafter relay 306 whose circuit was opened upon the deenergization of relay 305 retracts its armature opening the locking circuit of operated recording relays 505 to 520, inclusive, which in turn, open the initial operating circuits of magnets 401 and 404.

In response to the first impulse of the seventh or units series relay 300 deenergizes, opening the circuit of relay 307 which momentarily deenergizes opening the shunt around relay 321, permitting relay 321 to energize in the holding circuit of relay 322. Relay 321 at its lower armature and front contact now closes a circuit extending from ground at. the armature and back contact of relay 307, the lower armatures and front contacts of relays 3 17,. 319 and; 321, the lower armature and back contact of relay 323, conductor 334 to battery through the tens recording magnet 502. Magnet 502, upon energizing, locks to conductor 409 and rotates the tensrecording bar 540 thereby functioning in conjunction with the operated vertical bar 412 to lift the card 541. A moment later relay 321 opens its intermediate upper contact thereby opening the 'inagnet 503 to battery.

locking circuit of magnets 401 and 404. which thereupon release the operated vertical bar 412 and the coupling bar 410. The bar 537 is, however, maintained operated since the magnet 502 is locked to conductor 409.

With relay 300 deenergized relays 305 and 506 again energize, relay 506 locking in series with relay 505. When relay 300 again energizes relay 505 energizes. In this manner the recording relays are operated in pairs in response to the remaining impulses of the units series, it having been assumed that the units digit is 9, until the relays 521 and 522 operate and lock. lVhen relay 300 remains energized at the termination of the last impulse of the units series, relay 305 deenergizes closing the circuit of relay 307, which in turn, closes a circuit which may be traced from battery through the winding of relay 324, the innermost upper armature and back contact of relay 323, the innermost upper armatures and front contacts of relays 321- 309 to ground at the armature and front c011- tact of relay 307. Relay 324 locks in series with relay 323 to ground on conductor 311, but relay 323 being shunted does not energize so long as relay 307 remains energized.

lVith relay 324 operated circuits are closed in the manner before described in connection with tens registration for the magnets 405 and 402 which operate in succession, lock and eonjointly cause the rotation of the No. 9 vertical bar 418 in the ninth group of vertical bars. A moment later relay 306 whose circuit was opened by the deenergiza tion of relay 305 retracts its armature opening the locking circuit of the operated recording relays 505 to 522, inclusive, which in turn, open the initial operating circuits of magnets 405 and 402.

Since it is assumed that the desired line is in a full mechanical oflice and no stations digit is to be dialed, the class sequence switch 350 will have been positioned in position 10 in a manner to be described hereinafter. When, therefore, relay 324 energizes since the contact of class sequence switch cam 384 is open in position 10. the circuit of relay 307 becomes opened at the uppermost armature contact of relay 324. Relay 307 upon deenergizing opens the shunt around the winding of transfer relay 323 and this relay thereupon energizes in the holding circuit of relay 324. WVith relay 307 deenergized and relay 323 energized a circuit is closed from ground at the armature and back contact of relay 307, the lowermost armatures and front conta cts of relays 317 323, the lowermost armature and back contact of relay 325, conductor the right winding of units recording Magnet 503 energizes, locks to ground on conductor 409 and rotates the bar 542, which in conjunction with the operated bar 418 lifts the card 543. A. moment later relay 323 removes groundfrom the conductor 408 thereby releasing the operated magnets 405 and 402. These magnets thereupon release the operated bars 416 and 418.

Since pulsing relay 300 now remains energized, relay 306 deenergizes following the deenergization of relay 305 and removes locking ground from conductor 525 releasing the operated recording relays.

Had the desired line been a line of the class terminating in a manual office provided with a relay call indicator operators position, then a stations digit would have been dialled in addition to the other numerical digits and the class sequence switch 350 would have been set in some position other than 10. Therefore, when relay 324 energized upon the termination of the units series of impulses the circuit of relay 307 would not have been opened, and consequently the sender circuit would have waited for the dialing of another series of impulses. To illustrate the manner in which the stations impulses are recorded. it will be as sumed that the subscriber dials the stations letter 1V having the numerical equivalent 9. When, therefore, relay 300 dcenergizes in response to the first impulse of this series, the circuit of relay 307 is opened at the armature contact of relay 300 and relay 307 opens the shunt around relay 323. Relay 323 energizes and completes units registration in the manner previously described.

lVith relay 300 deenergized relays 305 and 506 again energize, relay 506 locking in series with relay 505. When relay 300 again energizes upon the termination of the first impulse of the stations series, relay 505 energizes. In this manner the recording relays are operated in pairs in response to the remaining impulses of the stations series, it having been assumed that the stations letter is having a numerical equivalent of 9. In response to the last impulse of the series the relays 521 and 522 operate and look. When relay 300 remains energized at the termination of the last impulse of the stations series, relay 305, deenergizes, closing the circuit of relay 307, which in turn, closes a circuit which may be traced from battery through the winding of transfer relay 326, the innermost upper armature and back contact of relay 325, the innermost upper armatures and front contacts of relays 323309 to ground at the armature and front contact of relay 307. Relay 324 looks in series with relay 325 to ground on conductor 311. The relay 325 being shunted does not energize so long as relay 307 remains energized.

With relay 324 energized circuits are closed in the manner previously described over contacts of recording relays and conductors 531 and 533, for magnets 405 and 402 which operate in succession, lock and eonjointly control the operation of vertical bar 418. A moment later relay 306 deener- .gizes retracting. its armature and opening at its uppermost armature contact opens the circuit of relay 307 which deenergizes opening the shunt around relay 325. With the removal of the shunt from relay 325, this relay energizes in the holding circuit of relay 326 and its lower armature and front contact establishes a circuit which may be traced from the armature and back contact of relay 307, the lower armatures and front contacts of relays 317 +325, conductor 336 to battery through the right winding of magnet-504. Magnet 504 energizes and locks to conductor 409 and rot-ates bar 544, which in conjunction with the operated vertical. bar 413-, lifts card 545. A moment later relay 325 opens its upper con-tact thereby opening the locking circuit of magnets 405 and 402 which thereupon release the operated bars 416' and 418.- The entire office and numerical designations of the wanted line have now been registered upon the unitary registering mechanism,

The circuits in this system are arranged to start the district and office selections following registration of the oflice code digits. lVhile the district and office switches are being positioned the subscriber continues to dial and register the numerical designation of the wanted line.

As soon as tran er relay 317 energizes following the completion of the dialing of the thou-sands digit a circuit is established from the upper inte-r'i'nediate armature and front contact of this relay to battery through the right winding of relay Relay 337 energizes and locks in a circuit from battery through its left winding and inner left armature contact to groin-d at the low-er contact of class sequence switch can]. 338. It will be recalled that the sequence switch 350 is standing in position 3. Relay-337 coinpletes a circuit from ground through its outer armature contact, left armature and back contact of relay 342, lower contact of cam 30S, winding of sequence switch magnet 350 to battery. Sequence switch 350 is energized in this circuit and commences to rotate to take up't'ho position corresponding to the class of the call being made by the calling subscriber, Said sequence switch will rotate as long as relay 342 remains deenergi-zed, This relay will only become energized when the particular contact of cams 339 and 340 corresponding to the selected cod-e card of the register is closed. In the present instance it is assumed that position 10 of sequence switch 350 represents a call of the full mechanical class. VV-he'n, therefore, sequence switch; 350 reaches position 10 a circuit is "closed from battery through the winding of relay 342, the upper right contact of cam 340, conductor 341, the lowermost contact of card 431 now in contact with the grid wire 421 to ground. Relay 342 becomes energized and locks in a circuit from battery through its winding and right arma-turecont act to ground at the upper contact of cam 338. Relay 342 at its left armature and back contact opens the above traced circuit of sequence switch 350 and this sequence switch comes to rest in position 10. Furthermore, relay 342 completes a circuit for advancing the sender sequence switch 310 out of position 1 into position 2. This circuit may be traced from battery through the winding of the magnet of sequence switch 310-, right contact of cam 343, front contact and left armature of relay 342, outer contact and armature of relay 337 to ground.

lVith the sender sequence switch in position 2 a fundamental circuit is closed as follows to control the selection of the proper set of brushes at the district switch: battery, through the left winding of relay 212, upper right contact of cam 251, lower left contact of this cam, right arnature contact of relay 207, brush 242, contact of cam 344, contact of cam 345,.winding of stepping relay 346, armature and contact of relay 347, to ground at the contact of care 348. Relay 212 energizes and completes a circuit from battery through the winding of sequence switch magnet 210, left contact of cam 215-, front contact and right armature of relay 212 to ground at the lower contact of own 213. The sequence switch 210 advances from position 3 into position 4 in which position relay 212 remains energized in a circuit from battery through its left winding, left armature and contact, the left contacts of cam 251, and thence to ground as described over the fundamental circuit. Relay 212 completes acircuit for the up'drive magnet 224 to cause the upward movement of the brush shaft 243. This circuit may be traced from battery, the winding of magnet 224, the right contact of cam 218, the right armature and front contact of relay 212 to ground at the lower contact of cam 213.

The stepping relay 346 is also energized in series with. relay 212 and completes a circuit from ground through its armature and contact, upper contact of cam 353, conductor 371, grid Wire 422, contact of card 431 in en gagement therewith, the No. 2 lead 362, lead 362 Fig. 3, the armature and back contact of the N0. 2 counting relay 37 6, winding of the No. 2 counting relay 377 to battery. Relay 377 becomes energized and completes a circuit for itself in series with relay 376 from battery through the windings of these relays, contact and armature of relay 377, lower contact of cam 349 to ground. Relay 377-, however, does not become energized since its Winding is shunted out by the direct circuit to ground through the armature of the stepping relay 346. As the brush shaft 248 approaches the first brush tripping position a brush 228 encounters the first metallic segment of commutator 230 and a circuit is closed as follows: battery, the left winding and left armature and contact of relay 212, upper left contact of cam 251, upper contact of earn 220, commutator 230, brush 228, to grouruit at the contact of cam 223. Relay 212 remains energized in this circuit and stepping relay 346 is shunted out.

Relay 346 deenergizes and removes the shunt from around the winding of counting relay 377, permitting this latter relay to energize in series with relay 376. The brush shaft 248 continues to advance and brush 228 engaging the next insulating segment permits the energization of relay 346. The stepping circuit is now extended by way of conductor 362 to the armature and front contact of relay 376, armature and back contact of relay 360, winding of relay 361 to battery. In a like manner for each brush tripping position approached by the brush shaft 248 a pair of counting relays is energized and locked until finally the No. 0 counting relay 359 becomes energized. Relay 359 closes a holding circuit for itself in series parallel with the windings of relays 358 and 347. This circuit may be traced from battery, through the winding of relay 359, whence it divides one branch leading through the winding of relay 358 and the other branch leading through the winding of relay 347 and thence through the contact and armature of relay 359, lower contact of cam 349 to ground. As the brush 228 encounters the next metallic segment following the energization of relay 359, the stepping relay 346 deenergizes and permits the operation of relays 358 and 347. Relay 347 opens the fundamental circuit and relay 358 completes a circuit from ground through its armature and contact, the contact of cam 378, winding of the magnet of sequence switch 310 to battery, advancing sequence switch 310 out of position 2 into position 4. As sequence switch 310 leaves position 2 the contacts of cam 349 are opened to permit the release of all counting relays that have been energized.

As soon following the opening of the fundamental circuit at the sender as brush 228 engages an insulating segn'ient of commucircuit is closed from battery through the winding of trip magnet 225 to ground at the contact of cam 221. ldagnet 225 energizes and rotates the trip spindle preparatory to tripping the selected set of brushes upon the next upward movement of the brush shaft 248.

lVith the sequence switch 210 in position 5 and the sequence switch 310 in position 4 the fundamental circuit previously traced is again closed to control group selection at the district switch. This circuit corresponds to the one heretofore traced with the exception that the contacts of sequence switches 210 and 310 are closed in different positions. Relay 212 upon energizing in the fundamental circuit closes a circuit for driving sequence switch 210 out of position 5 and into position 6. This circuit leads from battery through the winding of the magnet of said switch, left contact of cam 215. front contact and right armature of relay 212 to ground at the lower contact of cam 213. Relay 212 remains energized in position 6 of sequence switch 210 by means of the locking circuit from battery through its left winding, left armature contact, the left contacts of cam 251 to ground over the fundamental circuit as described. Relay 212 again closes the circuit for the updrive power magnet 224, over the right contact of cam 218. Brush shaft 248 is advanced and brushes 233, 234 and 235 are tripped into engagement with the terminals of the bank.

The stepping relay 346 which also energizes in the fundamental circuit completes a circuit from ground through its armature and contact, lower contact of cam 352, conductor 370, grid wire 423 and the contact of card 431 in engagement therewith, counting relay lead 368, lead 368 Fig. 3, armature and back contact of the No. 9' counting relay 366 to battery through the winding of the No. 9 counting relay 367. Relay 367 becomes energized and prepares a series holding circuit for itself and relay 366. As the brush shaft 248 approaches the first group of terminals, brush 227 engages the first metallic segment of commutator 231 and a circuit is closed from battery through the left winding and left armature contact of relay 212, upper left and lower right contacts of cum 251, commutator 231, brush 227 to ground at the contact of cam 223. Relay 212 remains energized and the stepping relay 346 is shunted out. Relay 346 deenergizes and permits the energization of relay 366 in series with relay 367. In a like manner succeeding pairs of counting relays are energized and locked as the brushes 233, 234 and 235 pass over succeeding groups of terminals. The No. 0 counting relays 347, 358 and 359 are finally energized and the fundamental circuit is opened. Relay 358 again closes the circuit including trunk.

cam contact 378 for driving the sender se quence switch 310 out of position 4 and into position 6. As sequence switch 310 leaves position 4 the contacts of cam 349 are opened and the energized counting relays rel'ease their 'armatures.

As soon following the opening of the fundamentalcircu t at the armature and contact of relay 346 as brush 227 encounters an insulating segment of the commutator 231,

relay 212 becomes deenergized and opens the circuit of the updrive magnet 224. Relay '21-2'a'lso closes acircuit from battery through the winding of sequence switch magnet 210, right contact of cam215, hack contact and right armature of relay 212 to ground at the lower contact of cam 213. Sequence switch 210 thereby advances from position '6 into position 7, whereupon a circuit is closed from battery through the right winding of relay 212, lower contact of cam 214, upper contacts of earn 208 to ground at the right armature and contact of relay 206.

Belay 212 energizes and completes a circuit It will be noted that relay 205 was energized in position 2 of sequence switch 210 in a circuit including the upper right contact 6f cam 209. The sequence switch 210 advances out of position 7 and into position '8, the relay 212 remaining operated if the first trunk, in the group upon the terminals of which the brushes 233, 234 and 235 are standing, is busy. In this case the test brush 235 is standing on a grounded test terminal the following holding circuit is closed for rela 21 2 extending from battery throngh the left winding and left armature contact'of relay 212, upper contacts of earn 222, brush 235 andthenc'e to the grounded "test terminal of the busy trunk. It will be noted that the upper left contact 222 does not close until position 7 This closure, however, takes place prior to the opening of the original energizing circuit of relay 212,

as the lower left contact of dam 212 opens when sequence switch 210 moves out of pos'ition 7 Relay 212 remaining energized a circuit is completed for the updrive magnet 224 from battery through the winding of "said magnet, right contact of cain 218,

rightfa'rmature and front contact of relay 212 aground at the lower contact of cam The brush shaft 248 is driven upwardly and brushes 233, 234 and 235 pass over the 'b'ankterininals in search of an idle When the first idle trunk is encountered, no ground-potential being found on the test "terminal 238 thereof, relay 212 'deenergizes and opens the circuit of the mag- "net-224. Relay 212 also closes a circuit as follows for driving sequence switch 210 out of position 8.into the selection beyond position battery, winding of the magnet of sequence switch 210, right contact of cam 215, right armature and back contact of relay 212 toground at the lower contact of cam 213. With sequence switch 210 in position 10 and sender sequence switch 310 in position 6 a fundamental circuit is extended from the sender to the office switch (not shown).

The fundamental circuit may now be traced in part from trunk conductor 239, bank terminal 236, brush 233, right contacts of cam 246, conductor 254, right armature and contact of relay 267, brush 242. contact of cam 344, contact of cam 345, winding of stepping relay 346, armature and contact of relay 347, contact of cam 357, brush 243, conductor 255, right contacts of cam 247, brush 234, terminal 237, trunk conductor 240, thence to the ofiice selector. The control relay of the 065cc selector and the stepping relay 346 of the sender energize in this circuit' for controlling ofiice brush selection.

hen the stepping relay 346 energizes a circuit is closed from ground through its armature and contact, upper contact of cam 352, conductor 372, grid wire 424 and the contact of card 431 in engagement therewith, counting relay lead 365, lead 365, Fig. 3, "the armature and back contact of the No. 4 counting relay 363 to battery through the winding of the No.4 counting relay 364. Relay 364 hecomesenergized and prepares a locking circuit for itself and relay 363. During the brush selection movement of the office selector, relay 346 becomes intermittently shunted in the well-known manner, whereupon the counting relays become energized in succession until finally the zero relays become operated. The fundamental circuit is then opened at the armature contact of relay 347 and a circuit is completed from ground through the armature and contact of relay 358 and the contact cam 373 for advancing sequence switch 310 into position 8, whereupon the actuated counting relays are released.

As soon as the circuits of the office selector are in condition for controlling group selection, the fundamental circuit previously traced is again established and relay 346 again energizes closing a circuit from ground at its armature contact, over the upper contact of cam 351, conductor 373, grid wire 425 and the contact of card 431 in engagement therewith, counting relay lead 356,

lead 356, Fig. 3, to battery through the winding of the No. 0 counting relay 359. Relay 359, upon energizing, locks in series parallel with relays 358 and 347, relays 358 and 347, however, remaining deenergized until stepping relay 346 deenergizes upon being shunted throngh the advance of the office switch shaft in its group selection movement. Upon the first shunting down of relay 346, relays 347 and 358 energize, relay .347 opening the fundamental circuit and relay 358 closing the circuit over the contact of cam 378 for advancing sequence switch 310 into position 10.

The selected ofiice selector functions in the well-known manner to hunt for an idle trunk extending to the office in which the desired line is located and upon finding such an idle trunk extends the fundamental circuit to the control relay of the selected incoming switch in which such trunk terminates. As soon as the fundamental circuit is thus established the sender stepping relay 346 again energizes and'closes a circuit from ground at its armature contact, over the lower contact of cam 353, conductor 379, grid wire 546 and the contact of card 535 in engagement therewith,

counting relay lead 547, lead 365, Fig. 3,

armature and back contact of the No. 4 counting relay 363 tobattery through the winding of the No. 4 counting relay 364. During the advance of the switch shaft of the incoming selector switch in its brush selection movement the sender stepping relay 346 is intermittently shunted in the wellknown manner until the zero counting relays 347, 358 and 359 operate, when the fundamental circuit is opened at the armature contact of relay 347 and the sequence switch 10 is advanced over the contact of relay 358 and the contact of cam 378 from position 10, into position 12.

When the circuits of the incoming selector are in condition for controlling group selection thereat, sender stepping relay 346 again energizes over the fundamental circuit and establishes a circuit from ground at its armature contact, over the lower contact of cam 355, conductor 383, grid wire 557 andthe contact of card 535 in engagement therewith, conductor 548, the left armature and back contact of relay 549, lead 550, lead 362 Fig. 3, armature and back contact of the No. 2 counting relay 376 to battery through the winding of the No. 2 counting relay 377. Relay 377 energizes, locking itself in series with relay 376. During the advance of the incoming switch shaft in its group selection movemen'; the stepping relay 346 is intermittently shunted until the zero counting relays 347, 358 and 359 operate. Relay 347 thereupon opens the fundamental circuit and relay 358 closes the previously traced circuit for advancing sequence switch 310 out of position 12 into position 14. In this connection it may be noted that if the thousands digit is even the grid wire 557 is always connected to, the right armature of relay 549, whereas if the thousands digit is odd, this wire is connected to the left armature of relay 549. Also for all hundreds digits above '4 the relay 549 is operated over a circuit extending through the relay, through a contact of a hundreds digit recording card such as 552 to the grounded grid wire This translation for controlling the incoming group selection is in accordance with the well-known practice such, for example, as fully disclosed in the patent to F. A. Stearn and F. J. Scudder hereinbefore referred to.

With the sender sequence switch in position 14 the fundamental circuit is closed to the final selector as soon as the incoming selector has completed its trunk hunting operation, when relay 346 energizes closing a circuit from ground through its armature, the upper contact of cam 354, conductor 380, grid wire 548, the upper contact of card 538, lead 549, lead 385, Fig. 3, armature and back contact of No. 1 counting relay 360 to battery through winding of No. 1 counting relay 361. Relay 361 energizes and looks through the winding of relay 360, but relay 361 being shunted at the contact of stepping relay 346 does not energize at this time. D'uringthe brush selection movement of the final selector, relay 346 is intermittently shunted until the zero relays 347, 358 and 359 energize, when the fundamental circuit is opened and the sequence switch 310 is advanced into position 16. I

In positions 16 and 18, respectively, final tens and units selections are controlled in accordance with the setting of the tens and units cards of the registering mechanism. The No. 8 counting relay 387 being operated over lead 386, lead 551 Fig. 5, grid wire 550, conductor 381 and the lower contact of cam 354 for controlling tens selection and the No. 9 counting relay 367 being controlled over lead 368, lead 554, grid wire 555, conductor 382 and the upper contact of cam 355 for controlling units selection.

When the complete connection has been established the sender sequence switch 310 reaches some position, such as 18 and a circuit is closed from ground through the contact of cam 369, brush 244, the upper left contact of cam 214 to battery through the right winding of relay 212. Relay 212 is energized and completes a circuit from battery through the winding of sequence switch magnet 210, left contact of cam 215 and the armature and front contact of relay 212 to ground at the lower contact of cam 213. Sequence switch 210 advances from position 10 into position 15. As the sequence switch 210 leaves position 11, the upper right contact of cam 209 is opened and the circuit of relay 205 is interrupted. Relay 205, however, remains energized by reason of a circuit closed from battery through its winding, contact and armature of relay 204 and the left armature and front contact of relay 205 to ground. Relay 204 it will be leaves position 11, relay 207 becomes deenergized and removes the busy condition from the multiple terminal of all sender switches to permit the sender which has just been used to be taken for use in extending subsequent connections. As soon as the'distliict sequence switch leaves position 10 the circuit previously traced through relay 300 is Opened whereupon this relay deenergizes, opening the circuit of slow releasing relay304 which after an interval retracts its armatures. At its outer right armature, relay 304 removes locking ground from conductor 311, whereupon all of the transfer relays 309 to 326, inclusive, are released. With relay 312 deenergized a circuit is closed from ground at the right armature and back contact of relay 300, intermediate armature and back contact of relay 304:, the intermediate armature and back contact of relay 312, through the left contact of cam 3&3 and winding of sequence switch 310 to insure that sequence switch 310 reaches its normal position. With sequence switch 310 in' its normal position, a circuit is closed from ground at the armature and back contact of relay 300, thence as traced through the contact of cam 374 and the upper right contact of cam 308 to battery through the winding of class sequence switch magnet 350 for advancing this sequence switch into normal position. At the time relay 207 deenergized and removed the busy ground from brush 241, the holding circuit of relay .302 was opened and ground was also removed from conductor 109, releasing all operated magnets of the registering mechanism. All apparatus of the sender is now in normal position and may be taken for use by another district link for controlling the establishment of another call.

With district sequence switch 210 in position 15 a talking circuit is established over the extended connection to the line of the called subscriber, ringingliaving taken place in the well-known manner. When the calling subscriber later hangs up his receiver the circuit of relay 204: is opened, relay 2041, in turn, severing the holding circuit of relay 205 and this relay becoming energized. Relay 205, thereupon, completes a circuit from ground through its right normal contact, right upper contacts of cam 219, winding of sequence switch magnet 210 to battery for advancing sequence switch 210 into position 18. The district selector switch is then restored to normal by means of the downdrive power magnet 226, the circuit of which is closed from battery through the winding of magnet 226, the right contacts of cam 219 to groundat the right normal contacts of relay 20 5. When the brush shaft 248 reaches its restored positioma circuit is completed from battery through the winding of magnet 210, the contact of sequence switch cam 217, segment 229, brush 228 to ground at the contact of cam 223. Sequence switch210 thereupon moves into position 1. As the sequence switch leaves position 16 the right contacts ofcam222 reopencd and the release ot-the otficeselector and other selectors used in the establishment of the connection is initiated in the well-known manner.

At the time relay 205 becomes deenergized it opens at its left armature and contact a circuit which up to this time has been helding relays 206 and 10 l'actuated. Relay 1051, upon deenergizing, completes a circuit as follows for restoring the individualline switch to its normal position: battery, through the winding and armature and contact of stepping magnet 10 lowermost armature and contact of relay 104,;rig-ht armature and back contact of relay 103, brush 107, segment 112 to ground. Stepping magnet 105 interrupts its ow-ncircuit and restores the brushes 106, 10?, etc. to their normal positions where the brush 107 disengages segment 112 and severs the operating circuit of magnet 105. The circuits of the system disclosed-herein have now been'completely restored to normal condition.

While a connection has been herein described to a particular office of-the exchange area, it'is obvious that the remaining 199 office code cards of the registering mechanism may be cross connected to the counting relays of the sender for controlling the connections to. other ofiices in much the same manner as previously described. To avoid complication of the drawings, only the first inthe second row of cards has been disclosed cross connected to the counting relay leads. The lowermost contactof each card may be connected as desired to the contacts of class switch cams 339 and 340, over the conductors shown for controllingthe positioning of the Class sequence switch inaccordance with the class of the desired connection. If the desired line terminates in a manual sci-lice provided withrelay call indicator, operators positions the numerical and stations digits oft-he desired line designation may be transmitted to the manual ofiice for operating the call indicator in the well-known manner. For this purpose the pulsing cams of the call indicator impulser of the sender (not shown) may becross-connected to, the lowermost contacts of the numerical and stations digit cards of the registering mechanism, these cross connections being indicated by the small squares attached to the several contacts. Other contacts of the several cards may be employed for controlling other selective functions of the sender in the same manner as the bank contacts of the step-by-step registers such as shown in thepatent to F. A. Stearn and F. J. Scudder hereinbetore referred to.

What is claimed is:

1. In a telephone system, a subscribers line, switching mechanism for extending connections from said line, and a central office sender for controlling said switching mechanism in accordance with call designations registered thereon, said sender having a unitary registering mechanism comprising cooperating elements for registering all digits of call designations.

2. In a telephone system, a subscribers line, switching mechanism for extending connections from said line, and a central oitice sender for controlling said switching mechanism in accordance with call designations registered thereon, said sender comprising an impulse recording device, a unitary registering mechanism comprisig cooperating elements for registering all digits of call designations successively recorded by said impulse recording device, and a progression switch for successively directing the digit records from said recording device to said registering mechanism.

3. In a telephone system, a subscribers line, switching mechanism for extending connections from said line, and a central office sender for controlling said switching mechanism in accordance with call designations registered thereon, said sender comprising a plurality of impulse recording relays, a unitary registering mechanism comprising cooperating elements for registering all digits of call designations successively recorded by said impulse recording device, and a progression switch for successively directing the digit records from said recording relays to said registering mechanism.

4:. In a telephone system, a subscribers line, switching mechanism for extending connections from said line, and a central ofiice sender for controlling said switching mechanism in accordance with call designations registered thereon, said sender comprising an impulse recording device, a unitary registering mechanism comprising cooperating elements for registering all digits of call designations successively recorded by said impulse recording device, and a plurality of transfer relays for successively directing the digit records from said recording device to said registering mechanism.

5. In a telephone exchange system, a subscribers line, switching mechanism for extending connections from said line, and a central office sender for controlling said switching mechanism in accordance with the otiice and numerical designations of wanted lines registered thereon, said sender having a unitary registering mechanism comprising cooperating elements for registering the otiice and numerical digits of all wanted line designations.

6. In a telephone system, a subscrihefs line, switching mechanism for extending connections from said line, and a central oiiice sender for controlling said switching mechanism in accordance with call designations registered thereon, said sender having a unitary coordinate registering mechanism comprising cooperating elements for registering all digits of call designations.

7. In atelephone system, a subscribers line, switching mechanism for extending connections from said line, and a central ofiice sender for controlling said switching mechanism in accordance with call designations registered thereon, said sender having a unitary registering mechanism comprisin cooperating elements for registering all digits of call designations, comprising a plurality of sepa 'ately operable registering elements and element selecting mechanism common to all of said elements.

8. In a telephone system, a suhscribers line, switching mechanism for extending connections from said line, and a central otiice sender for controlling said switching mechanism in accordance with designations registered thereon, said sender having a unitary registering mechanism for registering all digits of call desi nations, comprising a plurality of groups of separately operable registering elements, and operating means common to the elements of each group.

9. In a telephone system, a sni'iscrihefs line, switching mechanism for extending connections from said line, and a central of lice sender for controlling said switching mechanism in accordance with call designations registered thereon, said sender having a unitary registering mechanism for registering all digits of call designations, comprising a. plurality of separately operable registering elements, and means operable in accordance with the value of each digit to be registered and in accordance with the several digit series for selectively operating said elements.

10. In a telephone system, a subscrihers line, switching mechanism for extending connections from said line, and a central oftice sender for controlling said switching mechanism in accordance with call designations registered thereon, said sender having a unitary registering mechanism tor registering all digits ofcall designations, comprising a plurality of groups of separately operable registering elements, and operating means therefor including means com- 

